1. Field of the Invention
The present invention relates generally to temperature changing devices, and more specifically to self-cooling containers for cooling a product, such as a beverage.
2. Description of the Prior Art
It has long been desirable to provide a simple, effective and safe device which may be housed within a container, such as a beverage container, for the purpose of cooling a product, such as a beverage, on demand. Such self-cooling devices, even if effective, normally will cool the product with all of the attendant disadvantages thereof such as environmental hazard, bulkiness, expense and the like. Various types of devices have been developed to accomplish the desired self-cooling such as devices which rely on chemical endothermic and exothermic reactions, devices which require pneumatic circuits, devices using desiccant absorbing agents and water, and devices which rely on well-known electrical effects for both heating and cooling. Typical self-cooling devices known to Applicant for chilling beverages and the like are exemplified by U.S. Pat. Nos. 2,460,765; 3,373,581; 3,636,726; 3,726,106; 4,584,848; 4,656,838; 4,784,678; 5,214,933; 5,285,812; 5,325,680; and 5,331,817.
Self-cooling devices utilized in the prior art exemplified by the above-identified patents have generally been unsatisfactory. Some of the difficulties which have been encountered are that the devices (1) generally rely on toxic and environmentally unfriendly chemicals, (2) require very bulky pneumatic circuits and cannot economically be used in small containers such as beverage cans or foods cans, (3) are rather complex and are thus expensive to manufacture and maintain, and (4) are ineffective.
What is needed therefore is a device which may be inserted in a container for self-cooling which is simple, effective and safe.